Disclosed herein, in various embodiments, are undercoat layers useful in various imaging members and the imaging members themselves. Among other things, the undercoat layers can be readily removed, allowing the substrate to be more easily recycled.
Electrophotographic imaging members, i.e. photoreceptors, typically include a photoconductive layer formed on an electrically conductive substrate. The photoconductive layer is an insulator in the dark so that electric charges can be retained on its surface. Upon exposure to light, the charge is dissipated.
An electrostatic latent image is formed on the photoreceptor by first uniformly depositing an electric charge over the surface of the photoconductive layer by one of the many known means in the art. The photoconductive layer functions as a charge storage capacitor with charge on its free surface and an equal charge of opposite polarity on the conductive substrate. A light image is then projected onto the photoconductive layer. The portions of the layer that are not exposed to light retain their surface charge. After development of the latent image with toner particles to form a toner image, the toner image is usually transferred to a receiving substrate, such as paper.
A photoconductive imaging member may comprise a supporting substrate, an optional electrically conductive layer, an optional adhesive layer, a charge generating layer, a charge transport layer, and an optional protective or overcoat layer. One or more of these layers may also be combined or added to other layers to form the imaging member.
Conventional electrophotographic imaging members may also comprise an undercoat layer located between the substrate and charge generating layer. Some examples of conventional undercoat layers can be seen in U.S. Pat. Nos. 4,265,990, 4,921,769, 5,958,638, 6,132,912, 6,287,737, and 6,444,386, the disclosures of which are incorporated herein by reference in their entireties. In particular, such undercoat layers may be applied directly on the substrate.
Undercoat layers are desirable because they extend the functional lifetime for photoreceptors and enable the use of less expensive substrates. They may also assist in the adhesion of the photosensitive layers to the substrate. Undercoat layers also prevent foreign materials such as carbon fiber penetration into photoreceptors thus preventing “color spots.”
It may be desirable to recycle the substrate at the end of an imaging member's service life. However, the various layers deposited on the substrate of the imaging member must be removed before the substrate can be reused or sold. The process for removing these layers, known as substrate reclamation, is an expensive and somewhat time-consuming process. An example of a substrate reclamation process which includes lathing and cleaning photoreceptor substrates is disclosed in U.S. Pat. No. 5,346,556.
It would be desirable to develop an undercoat layer that allows for easy removal of the coating layers on the substrate without sacrificing performance of the electrophotographic imaging member.